docs: add missing cross-links for machine and human readability (#492)

docs/core-concepts/how-dograh-works.mdx

@@ -38,22 +38,22 @@ sequenceDiagram
 
 ## Key components
 
-**Workflows (Agents)**
+**[Workflows (Agents)](/core-concepts/workflows-and-agents)**
 The conversation logic. A workflow is a graph of nodes (conversation steps) connected by edges (conditional transitions). You define what the agent says, when it moves on, and what data it collects.
 
-**Runs**
+**[Runs](/core-concepts/calls-and-runs)**
 Every execution of a workflow creates a run. The run record holds the transcript, recording, extracted data, and cost information.
 
-**Telephony**
+**[Telephony](/integrations/telephony/overview)**
 The phone infrastructure. Dograh connects to your telephony provider (Twilio, Vonage, etc.) to place and receive calls. The audio streams between the caller and Dograh in real time.
 
-**Transcriber (STT)**
+**[Transcriber (STT)](/configurations/transcriber)**
 Converts the caller's speech to text in real time. Dograh sends the audio stream to your configured speech-to-text provider and uses the transcript to drive both the LLM and the final run record.
 
-**LLM Provider**
+**[LLM Provider](/configurations/llm)**
 Processes the transcript and the active node's prompt to generate the agent's next response. It also evaluates edge conditions to decide when to move the conversation forward.
 
-**Voice Synthesizer (TTS)**
+**[Voice Synthesizer (TTS)](/configurations/voice)**
 Converts the LLM's text response to audio and streams it back to the caller. The choice of TTS provider and voice is configurable per agent.
 
 ## How it fits together

docs/developer/environment-variables.mdx

@@ -175,6 +175,8 @@ Tracing activates automatically as soon as credentials are available — either
 
 ## Campaigns
 
+Controls concurrency for [Campaigns](/core-concepts/campaigns), Dograh's bulk outbound calling feature.
+
 | Variable | Default | Description |
 |---|---|---|
 | `DEFAULT_ORG_CONCURRENCY_LIMIT` | `2` | Maximum concurrent outbound calls per organization |

docs/voice-agent/pre-call-data-fetch.mdx

@@ -3,7 +3,7 @@ title: "Pre-Call Data Fetch"
 description: "Fetch customer data from your CRM or ERP before the call starts, so your voice agent can greet callers by name and reference their account details."
 ---
 
-Pre-Call Data Fetch allows you to enrich the call context with external data before the voice agent starts speaking. When enabled on the **Start Call** node, Dograh sends an HTTP request to your API as soon as a call is initiated. While the response is loading, the caller hears a ring-back tone. Once the data arrives, it is merged into the call's [initial context](/core-concepts/context-and-variables#initial_context) and becomes available as template variables in your prompts and greetings.
+Pre-Call Data Fetch allows you to enrich the call context with external data before the voice agent starts speaking. When enabled on the [**Start Call**](/voice-agent/start-call) node, Dograh sends an HTTP request to your API as soon as a call is initiated. While the response is loading, the caller hears a ring-back tone. Once the data arrives, it is merged into the call's [initial context](/core-concepts/context-and-variables#initial_context) and becomes available as template variables in your prompts and greetings.
 
 
 ## How It Works
@@ -17,7 +17,7 @@ Pre-Call Data Fetch allows you to enrich the call context with external data bef
 
 ## Configuration
 
-Open the **Start Call** node editor and expand **Advanced Settings**. Toggle **Pre-Call Data Fetch** and configure:
+Open the [**Start Call**](/voice-agent/start-call) node editor and expand **Advanced Settings**. Toggle **Pre-Call Data Fetch** and configure:
 
 | Field | Description |
 | --- | --- |