feat: make crosswalk and stop-line offsets solvable

Step 1 of the control-marking task, and deliberately server-only: no handle is
drawn yet. This project already shipped a range handle for `profile.interval`,
which compileGeometry ignores, so the control dragged and changed nothing. The
consumer comes first now.

Two kinds join the taxonomy — `junction-crosswalk-inset` and
`junction-stop-line-offset`, both on the existing `junction-approach` anchor. The
solver writes them onto the approach entry, `applyDirectJunctionPlans` carries
them onto the compiled approach, and `compileControlMarkings` reads them in place
of the module constants it used for every junction. They move markings without
reshaping the junction, so unlike width and cutback they deliberately do not
trigger a boundary recompute.

`applyJunctionConstraint` becomes an explicit switch. Its trailing `else` had
meant every kind that was not approach-width fell through to the cutback
validator, so a new kind would have been silently validated and written as a
cutback. The same non-exhaustive shape in the test fixture's `valueFor` is fixed
the same way, and now throws for an unnamed kind rather than answering with a
corner radius.

design.md's taxonomy is updated with it — a test asserts the two cannot drift,
which is what caught the omission.

Measured on a 41-road workspace with 8 crossings: both constraints change their
marking geometry, neither drags the other, and out-of-range blocks instead of
clamping. That measurement is not in the suite: the synthetic junction resolves
`junction_inset_m` to 0 because its crossing never binds to a plan, and the
committed OSM fixture has no crossings at all. The tests assert the wiring the
handles will depend on — values reaching the approach entry, distinct branches,
blocking diagnostics — and the gap is recorded in the test itself.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.trellis/config.yaml

@@ -0,0 +1,158 @@
+# Trellis Configuration
+# Project-level settings for the Trellis workflow system
+#
+# All values have sensible defaults. Only override what you need.
+
+#-------------------------------------------------------------------------------
+# Session Recording
+#-------------------------------------------------------------------------------
+
+# Commit message used when auto-committing journal/index changes
+# after running add_session.py
+session_commit_message: "chore: record journal"
+
+# Maximum lines per journal file before rotating to a new one
+max_journal_lines: 2000
+
+#-------------------------------------------------------------------------------
+# Session Auto-Commit
+#-------------------------------------------------------------------------------
+
+# Auto-commit behavior for session journal + task archive operations.
+# - true (default): scripts auto-stage and auto-commit journal / task changes
+#   after add_session.py / task.py archive runs.
+# - false: scripts do not touch git. Files (journal-*.md, task archive moves)
+#   are still written to disk; you decide whether to git add / commit.
+#
+# Use `false` if your project's .gitignore intentionally excludes `.trellis/`
+# and you want session data kept local-only, or if you prefer to review
+# staged changes manually before each commit.
+#
+# Accepts: true / false / yes / no / 1 / 0 / on / off (case-insensitive).
+#
+# session_auto_commit: true
+
+#-------------------------------------------------------------------------------
+# Task Lifecycle Hooks
+#-------------------------------------------------------------------------------
+
+# Shell commands to run after task lifecycle events.
+# Each hook receives TASK_JSON_PATH environment variable pointing to task.json.
+# Hook failures print a warning but do not block the main operation.
+#
+# hooks:
+#   after_create:
+#     - "echo 'Task created'"
+#   after_start:
+#     - "echo 'Task started'"
+#   after_finish:
+#     - "echo 'Task finished'"
+#   after_archive:
+#     - "echo 'Task archived'"
+
+#-------------------------------------------------------------------------------
+# Monorepo / Packages
+#-------------------------------------------------------------------------------
+
+# Declare packages for monorepo projects.
+# Trellis auto-detects workspaces during `trellis init`, but you can also
+# configure them manually here.
+#
+# packages:
+#   frontend:
+#     path: packages/frontend
+#   backend:
+#     path: packages/backend
+#   docs:
+#     path: docs-site
+#     type: submodule
+#   # For polyrepo / meta-repo layouts (independent .git in each subdir),
+#   # mark the package with `git: true`. The runtime treats it as an
+#   # independent repository for things like git-context display.
+#   webapp:
+#     path: ./webapp
+#     git: true
+
+# Default package used when --package is not specified.
+# default_package: frontend
+
+#-------------------------------------------------------------------------------
+# Channel worker OOM guard
+#-------------------------------------------------------------------------------
+# Default safeguards for `trellis channel spawn` workers. The guard runs
+# at spawn time (cleans expired idle workers, then enforces the live-worker
+# budget) and inside each supervisor (self-terminates a worker that stays
+# continuously idle past `idle_timeout`).
+#
+# Precedence: CLI flag > env var (TRELLIS_CHANNEL_WORKER_IDLE_TIMEOUT /
+# TRELLIS_CHANNEL_MAX_LIVE_WORKERS) > this config > built-in default.
+#
+# `idle_timeout: 0` disables idle cleanup (workers can sit idle forever
+# unless explicitly killed or given `--timeout`).
+# `max_live_workers: 0` disables the spawn-time budget check.
+#
+# `trusted_context_dirs` extends the `--file`/`--jsonl`/`--agent` containment
+# check beyond the worker cwd — useful when `.trellis/tasks` or
+# `.trellis/workspace` is a symlink to an external directory. Realpaths under
+# any listed dir are accepted in addition to cwd.
+# `auto_trust_trellis_symlinks: false` disables the narrow auto-trust of
+# `.trellis/tasks` / `.trellis/workspace` when either is itself a top-level
+# symlink (auto-trust is on by default).
+#
+channel:
+  worker_guard:
+    idle_timeout: 5m
+    max_live_workers: 6
+  # trusted_context_dirs:
+  #   - /work/user/trellis_workspace
+  # auto_trust_trellis_symlinks: false
+
+#-------------------------------------------------------------------------------
+# Codex (dispatch behavior)
+#-------------------------------------------------------------------------------
+# Codex-only knob; other platforms ignore it. Default ("auto") dispatches
+# trellis-implement / trellis-check / trellis-research sub-agents. This does
+# not rely on inherited parent transcripts: `fork_turns` remains
+# caller-controlled, while Codex's native SubagentStart hook injects task
+# context when trusted and child-side loading remains the fallback when it is
+# unavailable. Set to "inline" only to keep implementation and checks in the
+# main session. "sub-agent" remains a backwards-compatible alias for "auto".
+# Invalid explicit values safely use inline mode.
+#
+# In "auto" mode, dispatched sub-agents inherit the main session's model
+# unless you pin one. To use a cheaper/faster model for implement/check/
+# research sub-agent work, edit `model` / `model_reasoning_effort` directly
+# on the generated `.codex/agents/trellis-*.toml` files (see the commented
+# hint lines in those files) — there is no config.yaml knob for this,
+# `trellis update` preserves your edits across regeneration.
+#
+# codex:
+#   dispatch_mode: auto  # or "inline"; legacy alias: "sub-agent"
+
+#-------------------------------------------------------------------------------
+# Sub-agent context injection limits
+#-------------------------------------------------------------------------------
+# Caps how much task context (implement.jsonl / check.jsonl referenced files,
+# plus prd.md / design.md / implement.md) gets inlined into a sub-agent's
+# first prompt. Oversized files are truncated with a notice; once the total
+# payload cap is reached, remaining files degrade to index lines (path +
+# reason + size) instead of being inlined.
+#
+# All values are byte counts. `0` disables the corresponding limit.
+#
+# context_injection:
+#   max_file_bytes: 32768        # per implement.jsonl / check.jsonl referenced file
+#   max_artifact_bytes: 65536    # per task artifact (prd.md / design.md / implement.md)
+#   max_total_bytes: 131072      # whole injected payload; overflow degrades to index lines
+
+#-------------------------------------------------------------------------------
+# Per-turn prompt injection
+#-------------------------------------------------------------------------------
+# Escape hatch for the per-turn <workflow-state> breadcrumb. When a user
+# prompt contains the skip keyword as a standalone word (case-insensitive,
+# word-boundary match — "no-trellisfoo" does NOT count), the breadcrumb is
+# skipped for that turn only. Does not affect SessionStart or sub-agent
+# context injection.
+#
+# prompt_injection:
+#   skip_keyword: "no-trellis"   # "" disables the escape hatch entirely