Harden SMB file editing and transfers

[bifrost0x]

Summary

• add revision-checked, recoverable SMB text replacement with explicit consent and safe recovery details
• keep SMB navigation responsive during bulk transfers with separate control and transfer sessions
• make cancellation idempotent and finalize server-to-server cancellation from the authoritative response
• surface structured permission, conflict, timeout, availability, and known-size limit errors without exposing sensitive details
• add same-source Move with no silent overwrite and safe conflict handling
• expand diagnostics, documentation, unit, browser, and encrypted Samba coverage

Testing

• Full Python suite: 2,161 passed, 33 skipped
• Post-review affected Python suites: 150 passed
• JavaScript unit suite: 330 passed
• Full Playwright suite: 94 passed
• Post-review SMB Playwright suite: 8 passed
• JavaScript lint and vendored asset integrity checks
• Python dependency lock verification
• Encrypted SMB 3.1.1 Samba integration stack

Addresses the feedback in Discussion #99: #99

[chatgpt-codex-connector]

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