feat: /config command with source attribution

[ChrisRomp]

Summary

Adds a /config slash command that displays the effective channel configuration as a table with source attribution, showing where each setting came from.

What it does

• Shows merged config from all layers: defaults, config.json, dynamic channel, bot default, channel prefs, active session
• Each row shows Setting, Value, and Source columns
• Provider prefix only shown when the model actually came from channel prefs
• Workspace and bot show "runtime" source when resolved at session level

Key changes

• src/core/command-handler.ts: resolveEffectiveConfig(), formatConfigTable(), /config case
• src/core/command-handler.test.ts: 18 new tests for resolver, formatter, and command integration
• src/core/bridge-docs.ts: Added /config to commands topic

Example output

Channel Config -- #copilot
Source: config.json

| Setting         | Value              | Source          |
|:--|:--|:--|
| model           | `claude-opus-4.6` | session (active)|
| agent           | --                 | (not set)       |
| triggerMode     | `all`             | config.json     |
| verbose         | `Off`             | defaults        |
| permissionMode  | `interactive`     | defaults        |
| workspace       | `/path/to/ws`     | runtime         |
| bot             | `copilot`         | config.json     |

[Copilot]

Pull request overview

Adds a new /config slash command to surface the effective (merged) channel configuration in chat as a markdown table, including a “Source” column indicating which layer supplied each value.

Changes:

• Added resolveEffectiveConfig() to compute effective settings plus per-setting source attribution.
• Added formatConfigTable() and wired /config into command dispatch and /help output.
• Added test coverage for resolver/formatter behavior and basic command integration; updated bridge docs to list /config.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/core/command-handler.ts	Implements effective-config resolver + formatter and adds /config command + help text.
src/core/command-handler.test.ts	Adds unit/integration tests for /config, resolver attribution, and table formatting.
src/core/bridge-docs.ts	Documents the new /config slash command.

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[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

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