refactor: update search tool to match Obsidian CLI spec

Removed obsidian_search_with_context tool (not in CLI spec)
Updated obsidian_search to use exact CLI parameter names:
- query (required) - Search query text
- path (optional) - Limit search to folder path
- limit (optional) - Max number of files to return
- total (optional) - Return match count instead of file list
- case (optional) - Case sensitive search
- format (optional) - Output format: text or json (default: text)

Changed parameter names to match CLI:
- folder → path
- caseSensitive → case
- Added: total flag for match counts
- Removed: contextLines (not in CLI)

Files updated:
- src/tools/search.ts: Simplified to single search tool
- src/validation/schemas.ts: Updated searchSchema parameters
- manifest.json: Removed search_with_context, updated description
- tasks.md: Marked T048 as REMOVED

Total tools: 20 (was 21)
- User Story 1: 9 tools
- User Story 2: 11 tools (was 12)

Build: ✅ 0 errors
Validation: ✅ Manifest passes

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/validation/schemas.ts

@@ -144,11 +144,11 @@ export const moveRenameSchema = z.intersection(
 // Search parameters
 export const searchSchema = z.object({
   query: z.string().min(1, 'Search query cannot be empty'),
-  folder: optionalStringSchema,
+  path: optionalStringSchema, // Folder path to limit search
   limit: z.number().int().positive().max(1000).optional(),
-  caseSensitive: booleanFlagSchema.optional(),
-  contextLines: z.number().int().positive().max(10).optional(),
-  ...formatSchema.shape,
+  total: booleanFlagSchema.optional(), // Return match count instead of files
+  case: booleanFlagSchema.optional(), // Case sensitive search
+  format: z.enum(['text', 'json']).optional().default('text'),
 });
 
 // Tag search parameters