docs: Add documentation for the storage configuration block

[nstang43]

Description

The storage block is required in every Squadron configuration — omitting it produces:

Error: a storage block is required in the configuration, e.g.:

  storage {
    backend = "sqlite"
  }

However, there is no documentation for this block anywhere on the docs site. It's missing from:

• config/overview.mdx — not listed in the Block Types table
• No dedicated config/storage.mdx page exists
• getting-started/quickstart.mdx — not mentioned
• getting-started/docker.mdx — not mentioned

What the source code shows

From config/storage.go:

type StorageConfig struct {
    Backend    string `hcl:"backend,optional"`     // "sqlite" or "postgres"
    Path       string `hcl:"path,optional"`        // SQLite file path (default: ".squadron/store.db")
    ConnString string `hcl:"conn_string,optional"` // Postgres connection string
}

From store/factory.go, the two supported backends:

• sqlite — requires path (defaults to .squadron/store.db, or $SQUADRON_HOME/store.db when SQUADRON_HOME is set)
• postgres — requires conn_string (e.g., postgres://user:pass@host:5432/dbname). Uses pgx driver, auto-creates 12 tables via CREATE TABLE IF NOT EXISTS, sets pool to 25 max open / 5 max idle / 5min max lifetime.

Suggested documentation

Minimal addition to config/overview.mdx

Add storage to the Block Types table:

Block	Purpose
storage	Configure mission state persistence (SQLite or PostgreSQL)

New page: config/storage.mdx

SQLite (default):

storage {
  backend = "sqlite"
  path    = ".squadron/store.db"   # optional, this is the default
}

When SQUADRON_HOME is set, defaults to $SQUADRON_HOME/store.db.

PostgreSQL:

storage {
  backend     = "postgres"
  conn_string = "postgres://user:pass@localhost:5432/mydb"
}

Tables are auto-created on first use. Squadron creates 12 tables (missions, sessions, tool_results, etc.) using CREATE TABLE IF NOT EXISTS, so it can safely co-locate with application tables in the same database.

Attributes:

Attribute	Type	Default	Description
backend	string	sqlite	Storage backend: sqlite or postgres
path	string	.squadron/store.db	SQLite database file path
conn_string	string	—	PostgreSQL connection string (required when backend = postgres)

Context

We discovered this through reading the source code after trial-and-error. Our project co-locates Squadron tables alongside application tables in the same Postgres database, which works well since there are no table name collisions.