chore: remove outdated documentation and prep notes

- Deleted several draft and prep documents related to benchmarks, authority DPoP & mTLS implementation, Java analyzer observation, link-not-merge determinism tests, replay operations, and crypto provider registry.
- Updated the merge semver playbook to reflect current database schema usage.
- Cleaned up the technical development README to remove references to obsolete documents and streamline guidance for contributors.

docs/runbooks/replay_ops_prep_187_004.md

@@ -1,20 +0,0 @@
-# Replay Ops Runbook Prep — PREP-RUNBOOK-REPLAY-187-004 (Draft)
-
-Status: Draft (2025-11-20)
-Owners: Docs Guild · Ops Guild
-Scope: Capture required sections for the replay operations runbook once APIs are finalized.
-
-## Runbook sections to include
-1) **Prechecks**: confirm trust roots, air-gap status, Evidence Locker availability, and bundle integrity (`sha256`, DSSE verification).
-2) **Ingestion**: steps to POST replay records to Evidence Locker (`/replay/records`), expected responses, retry/backoff guidance.
-3) **Verification**: CLI commands (`stella verify --bundle`), Attestor verification call once available, interpreting results.
-4) **Replay/Compare**: `stella replay` and `stella diff` workflows, deterministic output locations, common failure modes.
-5) **Observability**: log/metric names to watch (to be filled after Evidence Locker/CLI finalize telemetry).
-6) **Escalation**: contacts for Scanner/CLI/Attestor/Evidence Locker guilds.
-
-## Dependencies
-- Replay payload schema (`docs/modules/evidence-locker/replay-payload-contract.md`).
-- CLI and Attestor prep docs for command/API details.
-
-## Handoff
-When APIs finalize, merge this content into `docs/runbooks/replay_ops.md` and retire this prep stub.