feat(tools): implement CRUD operations for thoughts and projects

* Add tools for creating, retrieving, updating, and deleting thoughts.
* Implement project management tools for creating and listing projects.
* Introduce linking functionality between thoughts.
* Add search and recall capabilities for thoughts based on semantic queries.
* Implement statistics and summarization tools for thought analysis.
* Create database migrations for thoughts, projects, and links.
* Add helper functions for UUID parsing and project resolution.

internal/tools/search.go

@@ -0,0 +1,69 @@
+package tools
+
+import (
+	"context"
+	"strings"
+
+	"github.com/modelcontextprotocol/go-sdk/mcp"
+
+	"git.warky.dev/wdevs/amcs/internal/ai"
+	"git.warky.dev/wdevs/amcs/internal/config"
+	"git.warky.dev/wdevs/amcs/internal/session"
+	"git.warky.dev/wdevs/amcs/internal/store"
+	thoughttypes "git.warky.dev/wdevs/amcs/internal/types"
+)
+
+type SearchTool struct {
+	store    *store.DB
+	provider ai.Provider
+	search   config.SearchConfig
+	sessions *session.ActiveProjects
+}
+
+type SearchInput struct {
+	Query     string  `json:"query" jsonschema:"the semantic query to search for"`
+	Limit     int     `json:"limit,omitempty" jsonschema:"maximum number of results to return"`
+	Threshold float64 `json:"threshold,omitempty" jsonschema:"minimum similarity threshold between 0 and 1"`
+	Project   string  `json:"project,omitempty" jsonschema:"optional project name or id to scope the search"`
+}
+
+type SearchOutput struct {
+	Results []thoughttypes.SearchResult `json:"results"`
+}
+
+func NewSearchTool(db *store.DB, provider ai.Provider, search config.SearchConfig, sessions *session.ActiveProjects) *SearchTool {
+	return &SearchTool{store: db, provider: provider, search: search, sessions: sessions}
+}
+
+func (t *SearchTool) Handle(ctx context.Context, req *mcp.CallToolRequest, in SearchInput) (*mcp.CallToolResult, SearchOutput, error) {
+	query := strings.TrimSpace(in.Query)
+	if query == "" {
+		return nil, SearchOutput{}, errInvalidInput("query is required")
+	}
+
+	limit := normalizeLimit(in.Limit, t.search)
+	threshold := normalizeThreshold(in.Threshold, t.search.DefaultThreshold)
+
+	embedding, err := t.provider.Embed(ctx, query)
+	if err != nil {
+		return nil, SearchOutput{}, err
+	}
+
+	project, err := resolveProject(ctx, t.store, t.sessions, req, in.Project, false)
+	if err != nil {
+		return nil, SearchOutput{}, err
+	}
+
+	var results []thoughttypes.SearchResult
+	if project != nil {
+		results, err = t.store.SearchSimilarThoughts(ctx, embedding, threshold, limit, &project.ID, nil)
+		_ = t.store.TouchProject(ctx, project.ID)
+	} else {
+		results, err = t.store.SearchThoughts(ctx, embedding, threshold, limit, map[string]any{})
+	}
+	if err != nil {
+		return nil, SearchOutput{}, err
+	}
+
+	return nil, SearchOutput{Results: results}, nil
+}