feat: add agent skills and guardrails functionality

- Introduced new tools for managing agent skills and guardrails, including add, remove, and list operations.
- Updated README.md to document new commands and usage patterns for skills and guardrails.
- Enhanced server configuration to support longer read and write timeouts.
- Increased maximum upload size for files to 100 MB and adjusted related configurations.
- Created database migrations for agent skills, guardrails, and their associations with projects.
- Updated relevant code files to integrate new skills and guardrails into the application logic.

migrations/017_agent_skills_guardrails.sql

@@ -0,0 +1,39 @@
+create table if not exists agent_skills (
+  id          uuid        primary key default gen_random_uuid(),
+  name        text        not null,
+  description text        not null default '',
+  content     text        not null,
+  tags        text[]      not null default '{}',
+  created_at  timestamptz not null default now(),
+  updated_at  timestamptz not null default now(),
+  constraint agent_skills_name_unique unique (name)
+);
+
+create table if not exists agent_guardrails (
+  id          uuid        primary key default gen_random_uuid(),
+  name        text        not null,
+  description text        not null default '',
+  content     text        not null,
+  severity    text        not null default 'medium' check (severity in ('low', 'medium', 'high', 'critical')),
+  tags        text[]      not null default '{}',
+  created_at  timestamptz not null default now(),
+  updated_at  timestamptz not null default now(),
+  constraint agent_guardrails_name_unique unique (name)
+);
+
+create table if not exists project_skills (
+  project_id  uuid        not null references projects(guid) on delete cascade,
+  skill_id    uuid        not null references agent_skills(id) on delete cascade,
+  created_at  timestamptz not null default now(),
+  primary key (project_id, skill_id)
+);
+
+create table if not exists project_guardrails (
+  project_id    uuid        not null references projects(guid) on delete cascade,
+  guardrail_id  uuid        not null references agent_guardrails(id) on delete cascade,
+  created_at    timestamptz not null default now(),
+  primary key (project_id, guardrail_id)
+);
+
+create index if not exists project_skills_project_id_idx on project_skills (project_id);
+create index if not exists project_guardrails_project_id_idx on project_guardrails (project_id);