feat: issue_list + workflow_run_list tools (#28, #29)

Adds the *_list partners that the existing *_get tools have been
missing. Same pattern as repo_list — owner allowlisted, capLimit
helper for pagination, next_page surfaced when the page is full.

internal/gitea/issues.go:
- ListIssues(owner, repo, args) hitting
  GET /api/v1/repos/{owner}/{repo}/issues with type=issues server-side
  so PRs don't leak in (gitea conflates them on this endpoint).
- ListIssuesArgs struct: State, Labels, Since (ISO 8601), Page, Limit.

internal/gitea/workflows.go:
- ListWorkflowRuns(owner, repo, args) hitting
  GET /api/v1/repos/{owner}/{repo}/actions/runs.
- Expanded WorkflowRun struct with DisplayTitle, Event, HeadSHA,
  HeadBranch, WorkflowID, RunNumber, UpdatedAt, Actor so callers
  can pin runs to a commit / branch without a second lookup.
- ListWorkflowRunsArgs: Branch, HeadSHA, Status, Event, Workflow,
  Page, Limit. Status/Event 'all' treated as no-filter.

internal/tools/issue_list.go:
- Default state=open, default limit=30 (matches repo_list).
- next_page returned only when len(issues) == limit.

internal/tools/workflow_run_list.go:
- Default limit=10 (most common use is 'what just happened',
  not paging).
- Returns runs + total + optional next_page.

Tests: table-driven for both — happy path, empty result, filter
combinations, allowlist rejection. workflow_run_list also asserts
the 'status=all is no-op' behavior (no query param emitted).

Closes #28
Closes #29

internal/tools/issue_list.go

@@ -0,0 +1,83 @@
+package tools
+
+import (
+	"context"
+	"encoding/json"
+
+	"gitea.d-ma.be/mathias/gitea-mcp/internal/allowlist"
+	"gitea.d-ma.be/mathias/gitea-mcp/internal/gitea"
+	"gitea.d-ma.be/mathias/gitea-mcp/internal/registry"
+)
+
+type IssueList struct {
+	c *gitea.Client
+	a *allowlist.Allowlist
+}
+
+func NewIssueList(c *gitea.Client, a *allowlist.Allowlist) *IssueList {
+	return &IssueList{c: c, a: a}
+}
+
+func (t *IssueList) Descriptor() registry.ToolDescriptor {
+	return registry.ToolDescriptor{
+		Name:        "issue_list",
+		Description: "List issues in a repo with optional filters. PRs are excluded (use pr_list for those).",
+		InputSchema: json.RawMessage(`{
+			"type":"object",
+			"properties":{
+				"owner":{"type":"string"},
+				"name":{"type":"string"},
+				"state":{"type":"string","enum":["open","closed","all"]},
+				"labels":{"type":"string"},
+				"since":{"type":"string"},
+				"page":{"type":"integer","minimum":1},
+				"limit":{"type":"integer","minimum":1,"maximum":50}
+			},
+			"required":["owner","name"]
+		}`),
+	}
+}
+
+type issueListArgs struct {
+	Owner  string `json:"owner"`
+	Name   string `json:"name"`
+	State  string `json:"state"`
+	Labels string `json:"labels"`
+	Since  string `json:"since"`
+	Page   int    `json:"page"`
+	Limit  int    `json:"limit"`
+}
+
+func (t *IssueList) Call(ctx context.Context, raw json.RawMessage) (json.RawMessage, error) {
+	var args issueListArgs
+	if err := parseArgs(raw, &args); err != nil {
+		return nil, err
+	}
+	if err := t.a.Check(args.Owner); err != nil {
+		return nil, err
+	}
+	if args.State == "" {
+		args.State = "open"
+	}
+	args.Limit = capLimit(args.Limit, 30)
+	if args.Page < 1 {
+		args.Page = 1
+	}
+	issues, err := t.c.ListIssues(ctx, args.Owner, args.Name, gitea.ListIssuesArgs{
+		State:  args.State,
+		Labels: args.Labels,
+		Since:  args.Since,
+		Page:   args.Page,
+		Limit:  args.Limit,
+	})
+	if err != nil {
+		return nil, err
+	}
+	out := map[string]any{
+		"issues": issues,
+	}
+	if len(issues) == args.Limit {
+		out["next_page"] = args.Page + 1
+	}
+	return textOK(out)
+}