Copy configuration schema v2_0_0 to v3_0_0 as baseline

[josecelano]

Part of EPIC: #1978 — Configuration Overhaul (schema v3.0.0)
EPIC position: Subissue #1 of 9. Foundation — all other subissues depend on this. Must be merged before any other subissue begins.
Spec: docs/issues/drafts/configuration-overhaul-copy-v2-to-v3-baseline.md

Goal

Copy the entire packages/configuration/src/v2_0_0/ module to packages/configuration/src/v3_0_0/ as the starting point for all breaking changes in the Configuration Overhaul EPIC. Also copy the crate-root logging.rs (which contains TraceStyle, setup(), and tracing_init()) into both v2_0_0/ and v3_0_0/ so each versioned module is fully self-contained (data types + behaviour). Wire v3_0_0 as the default schema version while keeping v2_0_0 available for backward compatibility during the transition.

Background

The Configuration Overhaul EPIC groups multiple breaking changes to the configuration schema. Rather than modifying v2_0_0 in place (which would break existing consumers), we create a new v3_0_0 module as a copy of v2_0_0. Each subsequent subissue in the EPIC applies its changes to the v3_0_0 module only.

This approach:

• Keeps v2_0_0 intact for any consumers that still need it
• Provides a clean baseline for all v3 changes
• Allows incremental migration — each subissue modifies only the v3 types
• Makes each versioned module fully self-contained (data types + behaviour)

Scope

In Scope

• Copy packages/configuration/src/v2_0_0/ → packages/configuration/src/v3_0_0/
• Copy packages/configuration/src/logging.rs into v2_0_0/logging.rs and v3_0_0/logging.rs
• Update packages/configuration/src/lib.rs to expose both v2_0_0 and v3_0_0 modules
• Wire v3_0_0 as the default schema version used by the application
• Update share/default/config/ files to reference schema_version = "3.0.0"
• Ensure all existing tests still pass (v2_0_0 unchanged)
• Add basic smoke tests for v3_0_0 deserialization

Out of Scope

• Any functional changes to the configuration types (those come in subsequent subissues)
• Removing v2_0_0 module (deprecated but kept for transition)
• Updating consumers outside packages/configuration (done in final-cleanup subissue)

Implementation Plan

ID	Task	Notes
T1	Copy v2_0_0/ directory to v3_0_0/	cp -r packages/configuration/src/v2_0_0/ packages/configuration/src/v3_0_0/
T2	Update v3_0_0/mod.rs to use crate::v3_0_0 internal paths	Fix module references within the copied files
T3	Copy logging.rs into v2_0_0/logging.rs	Crate-root logging.rs (TraceStyle, setup, tracing_init) → v2_0_0
T4	Copy logging.rs into v3_0_0/logging.rs	Same content as T3; v3 gets its own copy
T5	Update lib.rs to expose pub mod v3_0_0	Alongside existing pub mod v2_0_0
T6	Update default config files to schema_version = "3.0.0"	In share/default/config/
T7	Wire application entry point to use v3_0_0 by default	Update lib.rs or container.rs
T8	Add smoke tests: deserialize default v3 config	Verify v3_0_0 can parse the default config
T9	Run linter all and full test suite

Acceptance Criteria

• packages/configuration/src/v3_0_0/ exists as an exact copy of v2_0_0/
• lib.rs exposes both v2_0_0 and v3_0_0 modules
• Application uses v3_0_0 by default
• All existing tests pass (v2 unchanged)
• Default config files reference schema_version = "3.0.0"
• linter all exits with code 0