docs(rs-platform-wallet/e2e): consolidate TEST_SPEC.md spec evolution from PA + identity branches

Sources merged:
- PR #3571 commits (0186413, 3edff9e, 237f228, 8484d0b):
  Status standardisation across all non-Found PA entries; PA-003/006/006b
  assertion tightening; PA-005 trimmed to 4-round implementation with QA-007/008
  rationale; PA-004b/004c/009 status pinning.
- Trillian local commit fbf268063d (PR #3571 conceptual, local-only):
  New spec entries Harness-ID-1, ID-001b, ID-003b; Found-020 (PA-001b
  spec/impl drift pin); extended PA-001 implementation note re #3040 fee
  ceiling; PA-004c assertion rewrite (Skipped → registry-removed); PA-005b
  BLOCKED status with production API gap reasoning.
- PR #3578 commit 43c24ed:
  ID-001/002/003/005 upgraded from generic Wave A stubs to Pass entries
  with test-file citations; ID-004/006 upgraded with detailed deferral
  reasoning; ID-001c/005b/006b upgraded with P2-deferred rationale.

Major additions:
- Harness-ID-1 (P0): sweep_identities teardown regression pin.
- ID-001b (P1): setup_with_n_identities multi-identity helper spec.
- ID-003b (P2): concurrent identity-to-identity transfer nonce serialisation.
- ID-004/006/001c/005b/006b: STUB pinnings with deferral reasoning from #3578.
- ID-001/002/003/005: Pass status with test-file citations from #3578.
- Found-020: PA-001b spec/impl drift documentation.
- PA-003/006/006b: assertion tightening.
- PA-005: 4-round implementation alignment, rationale for 16→4 reduction.
- Status field standardisation across all non-Found PA entries.

Counts updated: P0=8, P1=17, P2=53, DEFERRED=1 (79 total).

Judgment calls:
- PA section: preferred #3571+Trillian over #3578 (more recent and comprehensive
  — #3578's PA section did not include Status fields or implementation notes).
- ID Status strings: preferred #3578's per-test citations for Pass entries over
  Trillian's generic "Wave A" stubs; merged both (Trillian's new entries +
  3578's specific test references) rather than picking one side.
- PA-005 scenario: kept 4-round version (#3571) over 16-round (#3578 base)
  as it reflects the implemented state documented on #3571.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: lklimek