fix(safety): make secret redaction source aware

[Liu-RK]

Scope

Scope boundary: Make tool-result secret redaction source-aware so ordinary source assignments remain readable while secret-bearing outputs stay masked.

Non-goals: Change filesystem permissions, add tools, broaden credential-pattern coverage, or modify documentation.

Branch

Base branch: main

Target exception: N/A

Issue

Linked issue: None

If None, reason: Direct regression fix for source-code token variables being replaced before the model could inspect them.

Release Note

Release note: Preserve ordinary token variables in source output while retaining secret masking for environment dumps and credential files.

Tests

Ruff: passed on all four changed Python files.

Pytest: 155 passed across secret redaction, dispatch envelopes, web fetch, trace recorder, and approval-event coverage.

Build: not needed; Python-only runtime change.

Regression tests: added

Notes: Coverage includes PHP token variables, known provider-key prefixes, .env reads, environment dumps, project config, and OpenSquilla config paths including $HOME.

The default test path remains offline, deterministic, credential-free, and safe for forks.

Maintainer Live Check

Maintainer live check: no

Surface: N/A

Maintainer-only note: No provider credentials or external services are required for this change.

Safety

No secrets, local-only artifacts, private prompts or transcripts, channel identifiers, session artifacts, non-public fixtures, or tests/_private/ contents are committed. Known provider-key formats and Authorization headers remain masked for every result source. Assignment masking remains enabled for .env files, shell profiles, environment dumps, and OpenSquilla configuration.

Third-Party Origin

Third-party origin: inspired-by

Details if non-none: Behavior was informed by NousResearch/hermes-agent at commit 2b7292ff0f5a61ceb212d28832883e2912949c96 (https://github.com/NousResearch/hermes-agent, MIT). No dependency, fixture, asset, or documentation was vendored.

Documentation Changes

No documentation files changed.

• Links point to existing repository files or stable external pages.
• Code fences and Markdown tables render correctly on GitHub.
• Examples avoid real secrets, local private paths, and private transcripts.

[github-actions]

Merge queue CI: success — run 35100576567, attempt 1.
Tested queue candidate: e32001d4d8d334156cc8333b17496f94e853671d. This result belongs to that combined tree, not necessarily the PR's current head.

The run summary lists reused suites and executed checks. A green PR check alone does not mean queue validation has passed.

[github-actions]

Merge queue CI: success — run 35101515129, attempt 1.
Tested queue candidate: 6e4362d2c69f6a33508facf3824be2c06aecca57. This result belongs to that combined tree, not necessarily the PR's current head.

The run summary lists reused suites and executed checks. A green PR check alone does not mean queue validation has passed.