Add remote SFTP editing with GlassEditorKit

[msitarzewski]

Summary

• integrate GlassEditorKit by local path for remote SFTP file editing
• keep every remote byte inside glas.sh's existing verified SFTP transfer layer
• add two-tier remote conflict detection and explicit user-owned resolutions
• add verified atomic replacement through OpenSSH POSIX rename while preserving ordinary no-clobber uploads
• record the implementation, acceptance evidence, and permanent Keychain/sandbox operating rule in the Memory Bank

Boundary and safety

• GlassEditorKit owns editor UI and conflict decisions only; it receives no SFTP client or credentials
• the streaming reader and editor configuration share one 8 MiB ceiling
• SFTP v3 nanoseconds remain unknown instead of inventing precision
• dirty or indeterminate conflicts never auto-resolve or silently overwrite
• the existing create-no-clobber upload path remains behavior-identical
• release packaging must replace the local package path with a pinned GitHub URL

Validation

• glas.sh macOS tests: 278/278 passed
• Citadel: 40 passed, 5 environment-gated skips, 0 failures
• GlassEditorKit UI: 102 passed
• GlassEditorKit Core: 297 passed, 1 package-known ReDoS issue
• macOS Debug build: passed
• visionOS Simulator build: passed
• signed manual open/edit/save acceptance: passed
• signed forced-conflict acceptance: passed
• git diff check and Memory Bank JSONL validation: passed
• no local foreground GUI automation run

Manual M4 acceptance

A remote file was opened, edited, and saved. The same file was then changed from a shell while the editor held local changes. glas.sh surfaced Overwrite Remote, Discard Local Changes and Reload, Save Local Copy, and Keep Editing instead of overwriting automatically.