docs: remove ROADMAP.md and scrub all references

## Why

ROADMAP.md was a static file that duplicated tracking information now
owned by Gitea milestones and issues. Keeping it created a maintenance
burden — references drifted out of sync with the actual state of work,
and agents were directed to read it when the source of truth had moved.

## Implementation Notes

All inbound references replaced with either the relevant Gitea milestone
("Skills & Agents") or removed where the context made them redundant.
Test assertions that verified ROADMAP.md content removed; test output
strings updated to drop the ROADMAP cross-reference instruction.

## Impact

Agents no longer read docs/ROADMAP.md at session start. Gitea milestones
and issues are the canonical source for roadmap and open-question tracking.

---

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/notes/factory-integration-decisions.md

@@ -147,7 +147,7 @@ IaC skills (category: `iac`) and Gitea integration skills (category: `gitea`) li
 | Chunk | Change |
 |---|---|
 | **2 follow-on** | Add issues 0013 (LESSONS.md) and 0014 (docs/spec/ + VISION.md refactor) |
-| **3** | Scope substantially expanded — see ROADMAP.md |
+| **3** | Scope substantially expanded — see Gitea milestone "Skills & Agents" |
 | **4** | WorkflowContext schema is a design prerequisite; docs/spec/ must exist before workflows reference it |
 | **5** | Role skills in `.agents/skills/` (category: roles); `core/agents/` for subagent definitions |
 | **6** | Eval runner, backfill, project LESSONS.md template, project docs/spec/ template, references/ template |