Add a global config at ~/.config/forge.toml

[bkearns]

Every layer that could set the task board's CQL host was tied to where forge is run from: an explicit argument, FORGE_CQL_HOST, or a .forge/config.toml found by walking up from the working directory. There was no way to configure a machine.

That is a real gap for an installer. The Ferrosa workbench provisions a database on a non-default port and could only reach forge by asking the user to export a variable, or by dropping a file into every repo they own. Anything else met

Error: connect to CQL ... Connection refused

against a database that was running the whole time.

The layer

~/.config/forge.toml, between the project file and the built-in default:

	source
1	explicit --cql-host / cql_host argument
2	FORGE_CQL_HOST
3	nearest .forge/config.toml, walking up from the cwd
4	~/.config/forge.toml
5	127.0.0.1:9042

A project config still wins, so a repo pins its own board and a machine-wide setting only applies where nothing more specific does.

debug_stop gets the same treatment. It shares the file and the schema, and honouring the global config for one key while ignoring it for the other would be the more surprising design.

Why that path

It matches the rest of the system rather than inventing a location — forge already reads ~/.config/ferrosa-memory.toml for its memory client, so its own settings sit beside it, with the same schema as the project file:

# ~/.config/forge.toml
cql_host = "127.0.0.1:47017"

One shape, two locations. A separate schema for the global file would mean two formats to document and keep in step.

Verification

Unit coverage for the precedence rule at every layer, blank-value fall-through, the resolved path landing at ~/.config/forge.toml, and both keys parsing from one body.

Beyond that, checked with the release binary against a live database from a directory with no project config and no exported variable:

before: Error: connect to CQL
after:  []

Precedence confirmed in both directions — a project config pointing at a dead port still beats a working global one, and FORGE_CQL_HOST still beats that.

Full workspace suite green (1304), build clean.

Note for review

dirs is added to forge-tasks, workspace-pinned like every other crate that uses it. The Cargo.lock change is the single corresponding line.