feat(lsp+tool-edit-file): multi-server diagnostics + per-edit auto-append

LSP extension:
- Multi-server aggregation: query ALL connected servers matching the
  file's extension (not just the first), merge diagnostics tagged by source
- Incremental sync: capture each server's textDocumentSync.change during
  initialize; compute prefix/suffix diff ranges for change:2 servers;
  full content for change:1 (generic, works for any LSP)
- New diff.ts: pure computeChangeRange + offsetToPosition (O(n), tested)
- Buffer sync: change(filePath, newText) sends didChange with post-edit
  in-memory content; openWithText for first open; tracks open doc text
- languageId mapping: extended with .rb/.rbs/.c/.cpp/etc. (was 'unknown')
- waitForDiagnostics: accepts text override + timeoutMs; returns
  { formatted, slow, timedOut }; polls for publishDiagnostics push
- DiagnosticsStore: hasReceivedPush/clearReceived tracking; formatFiltered
  with minSeverity (1=Error, 2=Warning) for edit_file integration
- LspService.getDiagnostics: service method for cross-extension use

tool-edit-file:
- After successful edit, calls LSP getDiagnostics with post-edit buffer
- Only appends diagnostics with severity ≤ 2 (errors+warnings, no noise)
- Appends slow warning (>10s): 'LSP is taking unusually long...'
- 60s timeout; graceful degradation when no LSP available
- Optional dep on @dispatch/lsp (getService pattern, not manifest depOn)

1468 vitest pass (was 1453, +15 new diff tests).

1 files changed, 16 insertions, 0 deletions

diff --git a/packages/lsp/src/language.ts b/packages/lsp/src/language.ts
index 214294e..a10dbed 100644
--- a/packages/lsp/src/language.ts
+++ b/packages/lsp/src/language.ts
@@ -26,6 +26,22 @@ const extensionMap: Record<string, string> = {
 	".sh": "shellscript",
 	".bash": "shellscript",
 	".zsh": "shellscript",
+	".rb": "ruby",
+	".rbs": "ruby",
+	".c": "c",
+	".h": "c",
+	".cpp": "cpp",
+	".cc": "cpp",
+	".cxx": "cpp",
+	".hpp": "cpp",
+	".hxx": "cpp",
+	".java": "java",
+	".kt": "kotlin",
+	".swift": "swift",
+	".php": "php",
+	".cs": "csharp",
+	".sql": "sql",
+	".dockerfile": "dockerfile",
 };
 
 export function languageId(filePath: string): string {