fix(ISA): remove stale TheRouter.hook.ts classifier references

[jbmml]

TheRouter.hook.ts was retired with the modes/tiers system (HookSystem.md: "retired entirely (commit 4dd0fbe19)… There is no successor classifier"), but the ISA skill still instructs the model to expect its GOAL_SIGNAL / INTERVIEW_ELIGIBLE emissions. This promotes each workflow's own already-designed fallback to primary, so the guidance matches reality with no behavior change.

Scope is deliberately ISA-only. The ~48 other "TheRouter" mentions across the repo are historical records (CHANGELOG, HookSystem.md, RouterSystem.md) that correctly document the retirement and are left untouched. Only the three operational instructions that tell the model to act on the dead signals are changed.

Changes

LifeOS/install/skills/ISA/Workflows/Scaffold.md:61
Before:

Classifier handshake: TheRouter.hook.ts may emit GOAL_SIGNAL: <1|2|3|4|none> in additionalContext. Trust as hint, re-validate via the detector above.

After:

Goal-signal detection: no classifier hook emits GOAL_SIGNAL anymore (TheRouter.hook.ts was retired with the modes/tiers system) — the four-signal detector above is the only mechanism.

LifeOS/install/skills/ISA/Workflows/Scaffold.md:92
Before:

• INTERVIEW_ELIGIBLE: false in the most recent TheRouter.hook.ts additionalContext block (the hook decided this is fast-path work). Line absent — e.g. a continuation prompt where the hook didn't re-fire — → infer eligibility from the running tier: true iff tier ≥ E3. This handoff is explicit text-passing; no shared state, no subprocess IPC. The model is the carrier.

After:

• Interview eligibility is inferred from the running tier: true iff tier ≥ E3 (below E3 is fast-path work, so the check is skipped). (TheRouter.hook.ts, which used to emit INTERVIEW_ELIGIBLE hints, was retired with the modes/tiers system — the tier rule, formerly the line-absent fallback, is now the sole determinant.)

LifeOS/install/skills/ISA/Workflows/CheckCompleteness.md:112
Before:

• If session additionalContext contains GOAL_SIGNAL: <1|2|3|4> (non-none) AND principal_stated_goal: in ISA frontmatter is empty/null → hard failure: "literal capture missed — classifier detected goal-signal but Scaffold did not preserve."

After:

• If principal_stated_goal_signal: in the ISA frontmatter is set (the four-signal detector fired at scaffold) AND principal_stated_goal: is empty/null → hard failure: "literal capture missed — the detector fired but Scaffold did not preserve the literal." (Formerly checked the retired classifier's GOAL_SIGNAL line; now an ISA-internal consistency check between the recorded signal and the recorded literal.)

Fixes #1524