TODO: cross-repo triage + slash-command routing + structured tiers (redo)

Previous commit (1fb4b9882) captured only the reset and lost my intended
additions due to a Read/Write race. Re-applying the four feature
requests from today's dogfooding session:

- Cross-repo `triage-all-repos` (real fix for the "many TODO.md files"
  surface area — single tool, per-repo SF dbs, unified read-only
  aggregation view).

- Slash-command routing fix (`/todo triage` is currently re-implemented
  by the agent's LLM, bypassing the typed backend; patches to
  commands-todo.js were silently inert).

- Structured tier/priority per triage item (today tiers exist only in
  LLM-prose appended to BUILD_PLAN.md; no parser-friendly field for
  "promote Tier 1 items").

- Phases-helpers stale-export error that fires on every SF run; needs
  either the missing export restored or a test that catches it.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

TODO.md

@@ -2,3 +2,109 @@
 
 Dump anything here.
 
+---
+
+## Cross-repo triage / unified backlog view
+
+Today's dogfood: a scan across active repos found **~40 TODO.md files**
+totalling **~10,000+ lines** across `/srv/infra`, `/srv/operations-memory`,
+`/home/mhugo/code/singularity-engine` (27 subdir TODOs, 9 000+ lines),
+`/home/mhugo/code/inference-fabric` (8 crate TODOs), plus per-repo
+singletons in ace-coder, dks-web, vectordrive, centralcloud, etc.
+
+The per-subdir files are **not noise** — most are substantive design
+specs scoped to their domain/crate/service. Collapsing them into a
+single root file would destroy useful structure.
+
+The actual gap: **no single way to see "what's queued across all the
+repos" at once.** Today this requires walking N repos by hand.
+
+Wanted:
+
+```
+sf headless triage-all-repos --config ~/.sf/repos.yaml
+```
+
+Where `~/.sf/repos.yaml` is a list of repo paths and (optional) per-repo
+priority. For each repo:
+1. If `TODO.md` has non-template content, run `triageTodoDump` in that
+   repo's SF db.
+2. After all repos triaged, emit a unified report: one row per backlog
+   item across all repos, sortable by priority / tier / inserted_at.
+3. Optionally produce a single `~/.sf/cross-repo-view.md` for quick
+   human reading.
+
+Per-repo SF dbs stay separate (each repo owns its work); the cross-repo
+view is read-only aggregation.
+
+## Slash command `/todo triage` should actually invoke the typed backend
+
+Observed today: `sf --print "/todo triage"` ran the agent, which read
+TODO.md and emitted a triage-shaped markdown response, but the agent
+**did not call `handleTodo` → `triageTodoDump`** — it re-implemented the
+flow in natural language via Read/Write tools. Side effect: a patched
+backend in `commands-todo.js` was bypassed entirely.
+
+Wanted: when a slash command has a registered typed handler in the
+extension surface (i.e. `handleTodo`, `handleNewMilestone`, …), the
+agent's prompt should *require* the call go through that handler rather
+than letting the LLM improvise. The handler can be invoked as a tool
+call so the LLM still has narrative space, but the side effects (DB
+writes, file scaffolds, etc.) come from the typed path, not from raw
+Write/Edit on TODO.md.
+
+Concretely:
+
+- In `slash-commands.md` (or wherever the slash dispatch prompt lives),
+  enumerate handlers and forbid the LLM from "doing the work" itself
+  when a typed handler exists.
+- Add an integration test that runs `sf --print "/todo triage"` against
+  a fixture TODO.md and asserts that `triage_runs` rows appear in
+  `sf.db` (i.e. the backend ran, not just the LLM).
+
+## Triage result needs structured tier/priority per item
+
+Current shape:
+
+```ts
+result.implementation_tasks: string[]   // titles only
+result.memory_requirements: string[]
+result.harness_suggestions: string[]
+result.docs_or_tests: string[]
+result.unclear_notes: string[]
+result.eval_candidates: { id, task_input, expected_behavior, … }[]
+```
+
+Tiers (T1 / T2 / T3) appear only in the LLM-prose tier list it appends
+to `BUILD_PLAN.md`. They are **not** present as a structured field per
+item. That blocks any downstream "for each Tier-1 item, scaffold a
+milestone" automation — the tier info is locked in prose.
+
+Wanted: extend the triage JSON schema so each implementation task is
+
+```ts
+{ title: string, tier: "T1" | "T2" | "T3", rationale: string }
+```
+
+and update `appendBacklogItems` + a future milestone-escalator to read
+the structured tier rather than re-parsing markdown.
+
+## Phases-helpers extension-load error on every SF run
+
+Every `sf …` invocation today prints:
+
+```
+[sf] Extension load error Error: Failed to load extension
+"/home/mhugo/.sf/agent/extensions/sf/index.js": The requested module
+'./phases-helpers.js' does not provide an export named 'closeoutAndStop'
+```
+
+Non-fatal (SF continues), but noisy and a sign of stale state. Either:
+
+- A recent rename of `closeoutAndStop` in `phases-helpers.js` wasn't
+  propagated to its caller, and `npm run copy-resources` quietly shipped
+  the partial state, or
+- A test gap doesn't catch missing exports from `phases-helpers.js`.
+
+Add an import-time sanity check (or a test that imports every entry
+in the extension index and asserts all required symbols resolve).