refactor(aidd-orchestrator): async-dev is 1915 lines with a 131-line router, four times the median

[blafourcade]

Slim aidd-orchestrator:00-async-dev, by far the heaviest skill in the framework.

Where the mass is

1915 lines across 31 files. More than twice 02-project-memory (871) and seven times 10-learn (153). Its SKILL.md is 131 lines, four times the median router.

For comparison, on origin/next:

1915  31 files  SKILL=131  aidd-orchestrator/00-async-dev
 871  36 files  SKILL= 50  aidd-context/02-project-memory
 378  10 files  SKILL= 32  aidd-context/04-skill-generate
 262   7 files  SKILL= 42  aidd-context/00-onboard   (before its rework)

Do it with #406

The same skill hardcodes aidd-dev in its routing regexes and its check-sdlc step, violating cross-plugin orthogonality (#406). The routing table is exactly what a slim pass rewrites. Fixing the address and shrinking the router touch the same lines: doing them apart means touching them twice.

The pattern

Apply what 00-onboard proved (branch feat/onboard-rework, plan in aidd_docs/tasks/2026_07/2026_07_08_onboard-tutorial-rebuild/):

• The description is the only always-on surface. Everything else loads on demand.
• Split a file only along a conditional-load boundary.
• The router carries a tiny title, a chaining schema, the action table, and transversal rules. Zero business logic.

The metric

Not lines on disk. Lines loaded per execution path.

Acceptance criteria

• Every current behavior is preserved.
• The router drops well below 131 lines, and carries no routing regex naming a plugin.
• Measure and state, in the PR, the lines read on the shortest and on the longest path, before and after.