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/context.go

@@ -0,0 +1,111 @@
+package tools
+
+import (
+	"context"
+	"fmt"
+	"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 ContextTool struct {
+	store    *store.DB
+	provider ai.Provider
+	search   config.SearchConfig
+	sessions *session.ActiveProjects
+}
+
+type ProjectContextInput struct {
+	Project string `json:"project,omitempty" jsonschema:"project name or id; falls back to the active session project"`
+	Query   string `json:"query,omitempty" jsonschema:"optional semantic focus for project context"`
+	Limit   int    `json:"limit,omitempty" jsonschema:"maximum number of context items to return"`
+}
+
+type ContextItem struct {
+	ID         string                       `json:"id"`
+	Content    string                       `json:"content"`
+	Metadata   thoughttypes.ThoughtMetadata `json:"metadata"`
+	Similarity float64                      `json:"similarity,omitempty"`
+	Source     string                       `json:"source"`
+}
+
+type ProjectContextOutput struct {
+	Project thoughttypes.Project `json:"project"`
+	Context string               `json:"context"`
+	Items   []ContextItem        `json:"items"`
+}
+
+func NewContextTool(db *store.DB, provider ai.Provider, search config.SearchConfig, sessions *session.ActiveProjects) *ContextTool {
+	return &ContextTool{store: db, provider: provider, search: search, sessions: sessions}
+}
+
+func (t *ContextTool) Handle(ctx context.Context, req *mcp.CallToolRequest, in ProjectContextInput) (*mcp.CallToolResult, ProjectContextOutput, error) {
+	project, err := resolveProject(ctx, t.store, t.sessions, req, in.Project, true)
+	if err != nil {
+		return nil, ProjectContextOutput{}, err
+	}
+
+	limit := normalizeLimit(in.Limit, t.search)
+	recent, err := t.store.RecentThoughts(ctx, &project.ID, limit, 0)
+	if err != nil {
+		return nil, ProjectContextOutput{}, err
+	}
+
+	items := make([]ContextItem, 0, limit*2)
+	seen := map[string]struct{}{}
+	for _, thought := range recent {
+		key := thought.ID.String()
+		seen[key] = struct{}{}
+		items = append(items, ContextItem{
+			ID:       key,
+			Content:  thought.Content,
+			Metadata: thought.Metadata,
+			Source:   "recent",
+		})
+	}
+
+	query := strings.TrimSpace(in.Query)
+	if query != "" {
+		embedding, err := t.provider.Embed(ctx, query)
+		if err != nil {
+			return nil, ProjectContextOutput{}, err
+		}
+		semantic, err := t.store.SearchSimilarThoughts(ctx, embedding, t.search.DefaultThreshold, limit, &project.ID, nil)
+		if err != nil {
+			return nil, ProjectContextOutput{}, err
+		}
+		for _, result := range semantic {
+			key := result.ID.String()
+			if _, ok := seen[key]; ok {
+				continue
+			}
+			seen[key] = struct{}{}
+			items = append(items, ContextItem{
+				ID:         key,
+				Content:    result.Content,
+				Metadata:   result.Metadata,
+				Similarity: result.Similarity,
+				Source:     "semantic",
+			})
+		}
+	}
+
+	lines := make([]string, 0, len(items))
+	for i, item := range items {
+		lines = append(lines, thoughtContextLine(i, item.Content, item.Metadata, item.Similarity))
+	}
+	contextBlock := formatContextBlock(fmt.Sprintf("Project context for %s", project.Name), lines)
+	_ = t.store.TouchProject(ctx, project.ID)
+
+	return nil, ProjectContextOutput{
+		Project: *project,
+		Context: contextBlock,
+		Items:   items,
+	}, nil
+}