fix: web search on DeepSeek and other reasoning modelsfeature/external-providers

A searched turn on a cloud reasoning model ended at the thinking: the
model emitted the tool call, but finish_reason: "tool_calls" landed on
the same SSE line as the include_usage block, so the single-event parser
returned that line as a usage chunk and the loop never saw the tool
finish. The parser now emits every event a line carries, so the search
fires.

Also in this change:
- Replay each round's reasoning_content on the assistant tool-call
  message, which interleaved-thinking models require to keep going.
- Add a per-provider replay_reasoning option (DeepSeek, SiliconFlow
  GLM-4.7+) to carry prior turns' reasoning_content when search is on.
- Add an on-demand diagnostic log gated by $LLAMACHAT_DEBUG_LOG.
- Record provider, usage_json and reported_cost_usd per reply, so a
  searched turn keeps every round's billed usage for external consumers.

1 files changed, 27 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6e9a831..34314f8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -34,10 +34,28 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   `model`. Token counts come from the stream's final usage chunk and power the
   cost readout; the model column records which model actually replied, so a
   switched conversation prices each turn correctly.
+- Three more columns on `messages`: `provider`, `usage_json` and
+  `reported_cost_usd`. The provider name is recorded when a reply finishes so
+  history stays self-describing even if a provider is later renamed or
+  removed; `usage_json` keeps every round's raw usage block from the stream
+  as a JSON array (a searched turn makes one API call per search round, and
+  all of them are billed, so all of them survive) for external consumers
+  such as the cost dashboard's ingester; and `reported_cost_usd` stores the
+  GUI's hand-entered-price estimate for the reply, summed across rounds, as
+  a sanity check only, staying NULL for an unpriced model rather than
+  claiming it cost nothing.
 - Per-provider `thinking_budget` option, for endpoints (currently SiliconFlow)
   that cap chain-of-thought tokens separately from the final answer. Unset
   providers skip the key entirely so other endpoints do not receive an unknown
   parameter.
+- Per-provider `replay_reasoning` option. When set and web search is enabled,
+  each prior assistant turn's `reasoning_content` is replayed on the next
+  request, which interleaved-thinking providers (DeepSeek, SiliconFlow's
+  GLM-4.7+) require when a `tools` key is present. Off by default so other
+  providers do not pay context and input tokens for thinking they ignore.
+- On-demand diagnostic log. Setting `LLAMACHAT_DEBUG_LOG` to a path appends
+  timestamped provider-error records (status, request body, full response) to
+  that file; unset, it writes nothing, so a normal launch never grows a log.
 
 ### Fixed
 
@@ -48,6 +66,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   which could be too small for a reasoning model. Non-local providers now send
   `max_tokens = 32768`, leaving room for both chain-of-thought reasoning and
   the answer.
+- A streamed tool call is now detected even when the provider puts
+  `finish_reason: "tool_calls"` on the same SSE line as the usage block (the
+  `include_usage` final chunk). The parser previously returned that line as
+  `usage` and dropped the finish signal, so a DeepSeek web search never
+  triggered and the turn ended at the thinking.
+- A searched turn now replays the model's `reasoning_content` verbatim on the
+  assistant tool-call message. Interleaved-thinking models (DeepSeek V3.2+/V4,
+  GLM-4.7+ on SiliconFlow) require this and stop answering — ending the turn at
+  the thinking — when it is dropped.
 
 Tool calling and reasoning output vary between providers. Web search on a
 cloud model may not work as reliably as it does with a local router.