chore: apply estate naming mandate — agent_instructions->bot_directives, 6a2->descriptiles (#301)

Applies the 2026-06-30 estate naming mandate (register:
`standards/CANONICAL-NAMES.adoc`) to echidna.

## Renames (git mv, history-preserving)

1. **`.machine_readable/agent_instructions/` merged into
`.machine_readable/bot_directives/`** — README.adoc, coverage.a2ml,
debt.a2ml, methodology.a2ml join the existing echidnabot.a2ml (no
filename collisions); the empty `agent_instructions/` dir is gone.
2. **`.machine_readable/6a2/` -> `.machine_readable/descriptiles/`** —
`6a2` is FULLY DEPRECATED; the family name is `descriptiles`.

## Reference updates

- `0-AI-MANIFEST.a2ml` — 6 path references (`[context-tiers]`,
`[canonical-locations]`, `[session-protocol]`)
- `scripts/collect-field-signal.sh` — `STATE_FILE` path
- `.machine_readable/contractiles/adjust/adjust.k9.ncl` +
`bust/bust.k9.ncl` — 2 paths each
- `bot_directives/README.adoc` — self-reference on the moved file

## Standards-pointer exception (deliberate)

`descriptiles/STATE.a2ml` line 1318 references
**hyperpolymath/standards**
`.machine_readable/agent_instructions/debt.a2ml` and is **kept as-is**:
standards has NOT migrated yet (verified 2026-07-01 —
`standards/.machine_readable` still has `agent_instructions/` + `6a2/`,
no `bot_directives/`). The earlier local commit fd54bbd wrongly rewrote
that pointer; this PR does not repeat that mistake.

## Deferred (pre-commit hook constraint)

20 files with stale `6a2`/path references could not be staged: the
pre-commit hook requires an `SPDX-License-Identifier: MPL-2.0` header +
canonical owner line in every staged `.md/.adoc/.rs` file, but these
docs are CC-BY-SA-4.0 (or lack the exact owner line), and licence-line
edits are owner-gated. They are: AFFIRMATION.adoc, RSR_COMPLIANCE.adoc,
CHANGELOG.md, .claude/CLAUDE.md, crates/echidna-core-spark/src/lib.rs,
docs/ARCHITECTURE.md, docs/PROVER_COUNT.md, docs/ROADMAP.md,
docs/decisions/2026-05-19-ci-baseline-triage.md,
docs/decisions/2026-05-30-chapel-rehabilitation.md,
docs/handover/{HANDOVER-INDEX,L3-LIVE-PROVER-CI-PROMPT,PHASE-3-PROMPT,PRODUCTION-WIRING-PLAN,README,STATE,TODO,llm-warmup-dev}.md,
docs/wiki/{FAQ,Home}.md. (Historical scanner artifacts
`reports/hypatia-findings*.json` were left untouched by design;
remaining `6a2` grep hits are hex-checksum false positives in
lockfiles/models.)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: hyperpolymath

…_readable/agent_instructions/README.adoc …hine_readable/bot_directives/README.adoc.machine_readable/agent_instructions/README.adoc renamed to .machine_readable/bot_directives/README.adoc .machine_readable/agent_instructions/README.adoc renamed to .machine_readable/bot_directives/README.adoc

@@ -32,7 +32,7 @@ Methodology-aware configuration for AI agents. Read by any AI agent
 == Relationship to Other Files
 
 * `AGENTIC.a2ml` says WHAT agents can do (permissions, gating)
-* `agent_instructions/` says HOW agents should work (methodology)
+* `bot_directives/` says HOW agents should work (methodology)
 * `bot_directives/` says what the gitbot-fleet does (fleet-specific)
 * `CLAUDE.md` says how Claude specifically should work (Claude-specific)
 

…eadable/agent_instructions/coverage.a2ml …ne_readable/bot_directives/coverage.a2ml.machine_readable/agent_instructions/coverage.a2ml renamed to .machine_readable/bot_directives/coverage.a2ml .machine_readable/agent_instructions/coverage.a2ml renamed to .machine_readable/bot_directives/coverage.a2ml

@@ -86,7 +86,7 @@ let base    = import "../_base.ncl" in
       { kind = 'verisimdb, table = "contractile_executions",
         schema = "contractile_execution_v1",
         aux_tables = [ "adjust_drift_history" ] },
-      { kind = 'drift_log, path = ".machine_readable/6a2/DRIFT.a2ml",
+      { kind = 'drift_log, path = ".machine_readable/descriptiles/DRIFT.a2ml",
         append_only = true },
     ],
 
@@ -141,7 +141,7 @@ let base    = import "../_base.ncl" in
             signature_required = true,
           },
         ],
-        signed_record_destination = ".machine_readable/6a2/ratification-<session-id>.a2ml",
+        signed_record_destination = ".machine_readable/descriptiles/ratification-<session-id>.a2ml",
         must_precede_work = true,
       },
 

…ne_readable/agent_instructions/debt.a2ml …achine_readable/bot_directives/debt.a2ml.machine_readable/agent_instructions/debt.a2ml renamed to .machine_readable/bot_directives/debt.a2ml .machine_readable/agent_instructions/debt.a2ml renamed to .machine_readable/bot_directives/debt.a2ml

@@ -88,7 +88,7 @@ let base    = import "../_base.ncl" in
       { kind = 'verisimdb, table = "contractile_executions",
         schema = "contractile_execution_v1",
         aux_tables = [ "bust_recovery_times" ] },
-      { kind = 'failure_log, path = ".machine_readable/6a2/FAILURES.a2ml",
+      { kind = 'failure_log, path = ".machine_readable/descriptiles/FAILURES.a2ml",
         append_only = true },
     ],
 
@@ -142,7 +142,7 @@ let base    = import "../_base.ncl" in
             signature_required = true,
           },
         ],
-        signed_record_destination = ".machine_readable/6a2/ratification-<session-id>.a2ml",
+        signed_record_destination = ".machine_readable/descriptiles/ratification-<session-id>.a2ml",
         must_precede_work = true,
       },